Not trying to be critical Mike, but if i don't say it someone else will. 99% of us wouldn't go to the trouble of pulling a intake and just replace one lifter, we'd do them all. Reason being if one is bad the others are close to it.
Another question i have is what did the face/bottom of the lifter you removed look like? Was it smooth, did it have unusual looking wear or cupping kinda like a dent. And did you look thru the lifter bore and see what the cam lobe looked like?