Should this be a sticky for wheel bolts?

[strelnik]

I found this information in a post when researching the size of wheel bolts for Bundts for my 1983 240D:

" The FSM only shows 2 lug bolts. the short bolt for the Steel Plate rim and the Light Alloy rim, shows it as part# 110 401 01 70, thread m 12 x 1.5, length 21. (looks by the picture, from where it seats in the rim seat to the end of the threads) fits models 107, 114, 115, 116, 123, 126, 201.
The longer bolt for the forged light alloy rim (Bundt) and a flat face 15 hole 14" rim. part# 108 401 00 70, threads m 12 x 1.5, length 29.5, fits models 107,114, 115, 116, 123, 126, 201. "

To break it down:
Size 1: Part# 110 401 01 70, thread m 12 x 1.5, length 21.
Made for :the Steel Plate rim and the Light Alloy rim, also fits models 107, 114, 115, 116, 123, 126, 201
Size 2: Part# 108 401 00 70, threads m 12 x 1.5, length 29.5
Made for: Forged light alloy rim (Bundt) and flat face 15 hole 14" rim, fits models 107, 114, 115, 116, 123, 126, 201

My questions:
1. What is a light alloy rim that is different from the Bundt rim? Anyone got a pic?
2. I have seen people selling 40mm bolts and 51 mm bolts for W123 cars. Is this because they measured the overall length (OAL) fo the bolt, as opposed to the threads or the seat area+threads?
Can we get a gallery of the most popular rims? II have some going back to 1951, but need some info on the w123 series.

Thanks!