The difference between the 80102 and the 60102 is that the 80102 is 8 cubic inches displacement (130 cc) where the 60102 is 6 cubic inches (100 cc). From memory the 60102 was usually 2 hp, but sometimes 2.25, and the 60202 (same engine with a different carburetor) was 2.25, but sometimes 2.5 hp. The external details (such as carburetor linkage and governor) are broadly similar for all four engines, but some of the parts are different in detail. In this case the governor spring is different, as AVB has pointed out.

Here is the illustration from the manual, of your carburetor linkage:
[Linked Image]


Here is your Illustrated Parts List:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6jmvGVJ1DajI.pdf

Here is your Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/lrvvA-wU7eL7hAxB91ObQ.pdf

Your engine was built on 21 July 1976 in Briggs Plant No. 3, in Rolla, Missouri.