uhh... from what I can tell, the only difference is that you can get the MG69-77 in blue or orange (with the wrong color comp stripe 🙄), where you can get the MG73 in really awful looking aged red or blue (this time the blue one has the wrong stripe).
MG69 has no stripe because from the name it is supposed to be a reissue of the 69 Mustang, which didn't necessarily have stripes. Cause if you wanted stripes, you would get the 69-77 (even though I'm pretty sure by 77 no Mustangs had stripes?)
I don't think Fender Japan really knows what's going on with their model names. Mine is a JG66, and has more in common with a 62 than a 66... no binding, dot inlays.
As far as I know all the basswood Japanese Mustangs ought to be of the same quality, it probably just has to do with trivial things like matching headstocks, paintjobs, and comparative rarity between the models, and depending on where this guy gets his guitars... Maybe they charge more to "age" that finish. Also that 65 reissue has a poplar body... finally... keep in mind it doesn't have cutaways, they charge more for that too apparently 😆
You haven't seen antigua much because most people are too boring to like it.
Slade