Bike rack on a Schwinn beach cruiser. What type of rack is this?

Trying to get a box or set of panniers for this rack, but most of them seem designed for the more common wire-frame style of rack (I don't know if it has a name or not).

Will this type of rack need an adapter or anything to make it work with typical bike bags?

Edit: Of course, right after posting this, I found out what this is. Leaving this post up with what I found out in case anyone else comes looking.

This is known as a vintage four-hole Schwinn bike rack. It is apparently a gamble whether a given set of modern pannier bags will work with it. Trunk bags are a bit safer bet, but still not guaranteed. The safest bet is of course the rack's compatible vintage basket, if one can be found.

Unfortunately, there are no adapters on the open market.