Hi Ernie,
Agree with Rodd's comment: if you want to really know all parts are in a 280 SL (including changes during the production), you need the factory Spare Parts List. 230 SL has only one book for chassis and engine, but 250 and 280 have two. You can order them through your local MB dealer, or the USA MB Classic Center.
250/280 SL chassis&body: Ref. L6510 4434 41 (price in Germany: 62 Euros)
M130 (280 SL) engine: Ref. L6510 4436 41 (price in Germany: 46 Euros)
Both books are in German/English/French, and show drawings of all parts with its part numbers.
A very good complement is another spare parts list from MB (although without engine parts
):
Ref. L6510 0000 04 (price in Germany: 19 Euros). It shows all parts still available, with current part numbers -because some parts have been replaced-, and current prices of the parts in Germany.
These books are really helpful when you need to order a part in the dealer, to compare prices with other suppliers, or simply to know if your car has the correct parts.
Regards,
Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432