Max,
It's a little confusing because AyA doesn't match exactly the Spanish pistol markings. The year code, normally applied at the proof house (with an asteric above) looks as though it was applied differently. Maybe it was applied at the AyA factory. Anyway, I have posted an AyA along with the date code table. I am assuming the "T-1" mark is the correct date code, making this particular gun from 1975. Notice how AyA didn't place the date code in the proof mark line. I hope this helps clear up the confusion with Spanish SxS dating
Sorry about the grainy photo, this AyA is also a Model 433..notice the chopper lump barrels