Teflon cuts easy, works like wood, a soft one at that.
Should work fine for the spacers. Might consider how slick it is, and if you use it for all of them could let your bed slide/wiggle around, or at least it may put a tad more strain on the bolts as the bed tries to move, but probably be fine.

Grigg


1951 GMC 250 in the Project Journals
1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-