I did this job some time ago.  If I recall correctly, the tack welds secure
the bushing once pressed into the control arm.  As the press fit isn't
necessarily that tight, I would be inclined to follow the Bentley procedure
and tack them in.

At the time I diagnosed the problem (no one could figure out where the
awful squeak was coming from on suspension compression) I was on a road
trip and in a very small town.  I guess on the trip the bushings went from
sqeaking to thunking, combined with noticeable camber changes.  Both
control arms were removed at a work bay (not a garage) and then I walked
them over to a nearby machine shop that removed the spot weld, replaced the
bushings (with a press) and re-tacked them in.  After an alignment at the
local tire shop, we were off.  If you're doing it yourself you will need an
unusualy large (I'm sure bentley lists the size) allen key or equivalent
socket.  I ended up buying one at the same machine shop that did the
control arm work.