Most jap cars including Toyota are 12 x 1.5mm.
Nissan are 12 x 1.25mm.
Fiat/Lancia and Alfa I think from memoery are also 12 x 1.25mm.
Most big Fords are 1/2"
Most big Holdens are 7/16th.
Normal taper is 60 degrees and "most" mags use this but not all tapers are 60 and some mags use shanks with no taper and some Nissans and Mitsubishis used a combination of shank and taper.
Most standard steel wheels are 60 degree taper as well.
The bottom line is thatyou do have a fair chance of reusing them and it is fairly easy to see if they are correct or not.