Differences b/t window regulators?

[Forza]

The driver's side window regulator that I pulled from my '83 coupe (to replace a pivot pin) is part no. 911 542 003 28. This part is available through Pelican but is special order from Germany only. The window regulator listed more commonly at Pelican and elsewhere is 911 542 929 03. Does anyone know what's the differerence between these two--both are scissors-type later regulators.

Also, just curious: Why the difference with the Targa/Cab regulators compared w/ the coupe?