Any way to know??

[JMBT]

CM 2250 demandated, smokes a bit after I idle to warm up, once I start down the road. It quits smoking entirely once I am cruising down the road. Doesn’t smoke at all after I have idled at a stop light, or anytime after the truck is warmed up and running, even in a hard pull or hard jake.
I have talked to several on the forum about it and the general consensus seems to be, failing valve guide seals.
My question: is there anyway, other then pulling the exhaust manifold, to be sure it is valve guide seals before I fork out $1000 for tools and pull all of the injectors???
Thanks