Seanoss, your pics on these mowers you acquired have been invaluable in working out why some white Mustang chassis (like mine) have no holes for the Mustang GTS cover and others have them present (blanked off with black plastic caps).
Interesting to note the round air filter housing on the first series white Mustang. It has a different decal as well. Obviously a carry over from the previous green base PT Mustang with the same white plastic engine top.
The second one which obviously shares the exact same base as the Mustang GTS (for production efficiency), going by it's blanked out screw holes for the GTS cover, also shares the square air filter housing with the GTS.
My theory, the whole engine and snorkel package were carried over onto the first white Mustang directly from the previous green based Mustang and the second series white Mustang shares the engine and snorkel package, sans cover with the GTS Mustang. I remember the features of the second series on the ones I saw on display in retail outlets like Bing Lee and Grace Bros department stores, back when they sold a great range of lawnmowers. Grace Bros even had the beefed up 505 pro in their range for about 1 grand !! Great memories.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!