The Velox was a Campagnolo entry level derailleur introduced for the 1972 model year. They quickly fell into disfavour and given that the shifters are also Velox, I assume they are OEM and would probably date this bicycle 1972-1974. The frame characteristcs indicate hi-tensile steel and in conjunction with the components (with the exception of the replacement front derailleur) are representative of an upper entry level model. Sometime during this period Stella switched from model names to numbers. Given the level and apparent era, it is probably a Stella Bordeaux which was 2nd from the bottom of the line in 1972.