normally smoke on a cold start up means the valve stem seals are worn

if the rings were worn i'd imagin it'd smoke constantly, larger amount of smoke depending on the more badly worn they are.

i had a problem with my old frst, only smoked if it came on boost then you backed off the throttle, would get a cloud of smoke out the back, oil seal in the turbo was goosed, new turbo on it and problem went away