Guides are possible,although with new seals it shouldn't be to much of an issue.biggest indication of seals or bad guides being bad is a cloud of smoke on start up that clears up quickly.when engine is shut off oil seeps past seals and ends up pooling on backside of the valves. Now if guides are completely thrashed then valve stems could flop around oil could get by the sears. But for them to be worn out enough to leave a constant trail of smoke out the tail pipe? I don't know about that,I've never run across that being the issue. But you never know right?!!
