Might be a stencil but it DOES have the front F, which only around half of these of that era had.
These are HIGHLY UNDERRATED splitbellkey horns. People go ga-ga over Chus and TT's...but quite honestly....these are as GOOD as a Chu (less problematic actually as they do not have the bow geometry which tends to cause a gurgle, as the Conn does)...and while I think the TT is the BEST splitbellkey ever made (the altos, not tenors)....the Martins are not far behind.
I never bought one to flip, because they are just not discussed much anywhere...but then a client approached me with refurbing one he had landed for $100 (silverplate, too).
I was impressed by it. Then oddly, someone else approached me with the same thing (actually not quite...they wanted to trade theirs in towards a Yas 23. I convinced them just to let me work up the Martin...as they'd save $100 over buy-trading for the Yama).
So, let's put it this way...given their invisibility on the market, and given this one is a stencil and quite possibly a relacq....$500usd is the max one would go for here in refurbished, playing shape. $350-400-ish if not refurbed, but clean and playing decently. A project one might fetch $175-200 (150-160 quid tops) here.
So if they are asking 200 quid and it doesn't need a total repad, it is a fair price.