Identifying R100 Heads

[Nourish]

Hello. I've bought a pair of '92 R100RS heads thru E Bay. How can I identify them to be sure they are as advertised - year and model ? Cheers

[mattcfish]

I'm not sure if later year heads have the casting year on them or not, all the 70's heads have it.
Heads that are 1985 and later have no rocker buttons on the heads. They're built into the rocker blocks at that point.
http://www.largiader.com/tech/rockers/
Incidentally, does anyone have a set of 1976 to 1985 rocker "buttons"? I have a good set of heads from a 1976 that are missing their's.