Followup....
Well it's been nearly a month since my original post on this subject
about installing parts from an Ace Hardware "Delta single lever Full
repair kit".
The faucet spout became more difficult to swing from side to side during
that time. If I tried to move it in the morning before running any water
through the faucet it was noticably stiff to move and emitted a very
nonmetallic "rubbery" squeeeek.
I had enough of this so I gave up and purchased a set of genuine Delta
branded spout body O-rings from an online supplier. (Delta P/N RP25)
They arrived a couple of days ago.
I installed those Delta spout body O-rings this morning and the spout
now swings easily and smoothly, just as it had for some twenty years
prior to installing the O-rings from the Ace Hardware kit.
I did note that the new Delta branded O-rings were a greyish color, not
the usual O-ring black like the Ace Hardware ones. Maybe they've got
some teflon or something mixed into their "rubber" compound.
Anyway, I'm pretty confident that the problem is now solved.
I'm not ranting against Ace Hardware as I doubt that they had much to do
with the O-ring material their faucet repair kit supplier used, and
we're not talking big bucks here, The Ace "full ki"t only cost about $9
and the Delta O-rings set me back about $15, most of that being the
minimum S&H charge.