Hydraulic Roller Lifter testing...?

NO answers and I'm not an expert on thie
AFIK all retro lifters (that are made in USA) are made in the same place
IDK if there are foreign retrofits but that's a good question
do try that drill press test on a good and suspected lifter and post back
yoy should be able to feel the difference in pressure with your hand on the feed
if buying new lifters find out who actually made them and where