In the USA, Porsche began using Brembo Calipers on Street legal Porsches with the 930 in 1979. All Porsches after '89 use Brembo Calipers.
There are two basic Brembo designs used for the Porsche. The Early style used up to early '89 and the newer style beginning in late '89 and still used today.
The important difference between the two is the "scraper ring" used on the early style and the "dust boot" used from '89 to 97. Both parts are designed to do the same job. Protect the Piston.