JALinker

I have located a Snapper RER for a little less than $300, not sure of the vintage, guy that is selling it says it needs some carb work...  it is an 8-HP Tecumseh.  I know the carb is partially disassembled, the bowl is in the seat, he says it needs a new float.  Should I just purchase a new carb and be good to go, and then which can I get, float or diaphragm?  are they interchangeable?

He also has an older RER, a comet 30, I think it was, with an 8-horse briggs on it for a little less money...  He was insure what it'd need to get going again.

I am not sure the vintage of either of these, but I know the tecumseh-engined one has the new(er) blade interlock pedal assembly thing, and the comet does not.

They are both electric start versions.  

What specifically should I look for on these?  How can I tell the vintage?  If I go back and look at them, is there a way I can bring more info here and ask someone which would be the better one to get?

Thanks!!