The plastic parts of the rad is the upper and lower caps. From what I understand the plastic-to-metal rad bound is only good for about 6yrs.

If you don't want plastic end caps, you need to see if a shop can rebuild the oem one you have now, or grab one from a wrecking yard and have it rebuilt. A rebuild should run about the same as buying a new one w/plastic end caps, maybe less.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed