Hi and welcome.
Rule number one concerning Matsumoku made instruments is, "specifications are subject to change without notice".
Yes we have catalogues and a lot of data compiled by a lot of dedicated folks in the forum...BUT...sometimes, just when you think you have a handle on it, everything goes pear shaped! We're always finding exceptions.
Pictures would help a lot here, but yes, the label would confirm this is a Mats, they did not go out of business until 1987. The serial # indicates a 1980 or possibly an '81 build. Assuming that the label was current at he time of the build and not an old one from stock, that would seem to contradict
Mozart's research that the VA-10 was made in 1982.
However, concerning the round instead of oval sound hole, most likely, this is simply an earlier version, possibly a limited run to test market acceptance, before they switched to the oval design to 'sex' it up a bit and release it formally.
Construction details as you stated are correct, and AFAIK all tops are solid wood not plyw...uh, laminate.
I wouldn't worry if this is genuine or not. It looks to be the real deal. If you like it, grab it. The Vantage line is excellent value.