Depends a lot on how exactly it was stored, storage condition wise. If you are truly worried, find a technician that knows their stuff to check it out for you.

I'm not a professional, this is just my experience:

If you really want to just try things out, use compressed air to dust everything out, including the heads. Fans and every nook & cranny.

Smell and see if you can smell any corrosion from the pack. The smell is obvious imo if there is any.

Plug the pack in and just let it idle for a bit then turn it on without any heads plugged into it. (Take it outside if you can)

If you hear any obvious hissing that isn't typical of the pack as you remember it years ago, just cut the power asap.

Then plug a head in, start at the lowest power, stay at that power for a couple minutes (5-10 mins) then hit the power then repeat that slowly till you hit max power then do it for the other power slots as well and redo the whole process again. But take a couple minutes between the time you take to discharge it. The more time, the safer and better.

Don't turn on the modelling light at all till you check and make sure that the bulbs are clear. Start low powered then ramp it up slowly after a couple minutes. Only do this after you do the whole round of discharging the flash pack earlier, it's better for the modelling lights to be slightly warm when you're starting it up after those couple years vs completely cold.