transmission slipping on 1996 Chevrolet 1500 Pickup

Can a clogged trans. filter cause the transmission to slip??-this truck has 213,000 miles on it- had the origional tranny replaced at about 105,000 miles.

Technically yes, a plugged filter will restrict the oil flow into the transmission and cause slipping, however if the filter is plugged, it is from debris in the transmission and you probably have other issues.
It's not too expensive to have thi service done, but check the fluid level first, make sure it isn't low. My guess is this won't fix the slipping, and you might be better off getting the transmission issue diagnosed by a transmission shop.