Indeed... don't hammer 'em in. Don't try to use a vise. And don't try to do it yourself unless you're very familiar with the procedure. VERY easy on a Volvo to not only wreck the new needle bearings, but worse is bending the yokes on the driveshaft. Have someone who knows what they are doing do the job. Money well spent.

That said though...you say you have these sitting on your workbench, But you don't mention that yours are bad. Are they? If not, don't fix 'em. IF the old ones have grease zirks, go ahead and lube 'em up. But no need to fix that which ain't broke. They will give you some warning before thay go.

-Matt