'66 20 hp Lower unit seal kit discrepancy

Hi all. I'm about to reseal the LU on my '66 FD-20C 20 hp, but I noticed that the part numbers in my parts catalog and the ones listed in the Sierra replacement kit available here at iboats don't seem to match. Have the old OMC parts numbers in my manual been superseded by the new ones shown below in the Sierra kit? Thanks.

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/381415/38141500001.htm


iboats says I need Sierra replacement kit: #18-2684

Kit Contains: Manual says I need:

(1) 18-0882 Shift Rod Gasket - replaces O.E. # 304764
(1) 18-2032 Oil Seal - replaces O.E. # 321788 #302545
(2) 18-4248 Washer - replaces O.E. # 311598
(1) 18-7100 O-Ring - replaces O.E. # 301877
(1) 18-7120 O-Ring - replaces O.E. # 307853
(1) 18-2031 Oil Seal - replaces O.E. # 321787 #307563
(1) 18-2534 Spaghetti Seal - replaces O.E. # 309044