I’ll start by correcting my typo. ear - era.
I don’t think there will be a problem with the valve stems and valve springs or any valve float issues unless the engine is way up there in miles and/or has seen some severe overheating in the past.
As a foreign car guy (the word foreign is iffy anymore) I haven’t dwelled too much on the domestics much like a full time Ford or Chevy guy might but I do remember on occasion getting into a couple of flat cam lobe situations with small block Chevys way back when. Replacing the cam and lifters fixed the engines right up but in both of these cases the engines were known to be carrying good oil pressure and good compression.
If flat lobes are the problem and this has gone on for a long time the valve stem face should be carefully examined for mushrooming though. In cases where the stems are mushroomed a little the lifters may be damaged and of course in the case of the stems this would mean a complete valve job and replacement of any damaged stem valves that may exist.
It seems to me the shop the OP mentions is going about some of this backwards. The cam lobes can be easily checked with a valve cover off and the intake manifold does not have to be removed to change the lifters out. There’s a tool that fishes them out through the pushrod hole.
Just my opinion and hope it helps.