The Mark VII was never intended to be a VI in any way, it is an entirely different model designed by leon Selmer & Michael Nouaux, premier solo saxophonist of the Guard Republicaine Band, Paris. Fred Hemke did NOT design the Mark VII as many would have you believe although he may have given advice when asked & no doubt he was as a Selmer clinician. I have his reviews of the VII alto when it came out & they were quite good. However, we're talking tenors here, not altos.
The VII tenor was not well received as it was compared to a VI by VI players; they didn't like the keywork, mainly the spatula or table keys & the low C & Eb keys. If you had smaller hands those keys could be a stretch & perhaps awkward to some. the neck angle was changed too & many didn't like that plus it is a heavier horn but very well built with many improvements. The acoustics were/are very good, it has a different taper to facilitate higher altissimo, plays better in tune, louder more powerful horn with a very core Selmer sound. Personally I think them good horns, the VII tenors, and I do not find the keywork any more difficult than a vintage Buescher, Conn or Martin. In fact the VII keywork even on the tenors to me is easier to work than a vintage horn with the older keywork, and many folks love their vintage horns. A silverplated or better still sterling silver Serie III Selmer neck makes a big difference on a VII tenor as far as the angle is concerned and the sound. I really like the results on my VII alto with a sterling III neck although the orig VII alto neck works quite well too. In any case the VII tenors I have heard played and the one I got to play once were very good horns & sounded quite good. They are being re-discovered & going up in price especially the earlier production VII's as they are generally engraved horns & thought to be among the better ones made which is not to say a later one can't be just as good. production errors tend to be more prevalent as the run goes on.
Were I to run up on a good early VII, an engraved one to match my early VII alto and it was reasonably priced I would be sorely tempted to buy it even if I had to hock something, lol. They sound very good or at least a good one will, and you can get good & not so good horns in every model.
The alto VII's are very different from the tenors in that the keywork is far less a problem (if at all) and I like the keywork, fits my hands like a glove. I've had a long bow VI alto in the M119XXX range and the VII alto I have now M254XXX (1975) in my opinion out plays it completely. I was lucky enough to find it (the VII alto) as new/old stock still in the plastic back in 2000 at a local Selmer dealer that had been around for nearly 60 yrs. It came in a treypac case, fully engraved, dark blue around the S in honey gold lacquer. I bought it on the spot and have never regretted it and will part with it when it's pried from my cold dead hands. The VII altos are great horns, but they too got an "assumption" bad rep early on from the complaints on the tenor. Folks assumed the altos were like the tenors and they weren't, and the tenors weren't near as deserving of the rep either.
As for the engraving & the blue S.....you'll find it on all the European Selmer VII's but not on many of the American assembled ones at Elkhart. In fact even the later VI's had no blue around the S at Elkhart. the blue wasn't put on in Elkhart as a cost saving measure as was the lack of engraving, but it continued to be done at the Selmer factory for the European horns.
The VII tenor would not be my first choice for a tenor had I excess funds to spare, I'd rather have a good VI for a tenor, BUT....I certainly wouldn't turn down a good VII tenor either if the price was right & would be deeeee-lighted were one given to me (which will never happen alas) However, the VII alto is my very favorite, there may indeed be an earlier VI (and I like the early VI altos) that might supplant the VII in my affections but to date I haven't found it yet.