I think this is old folic acid only.

For a while Methylfolate was not available to OTC makers.

So most mixes are the old folic acid. They would have a huge batch made, and to change that would be expensive for them.
Also the cost of methylfolate is pretty steep... Single content methylfolate OTC tabs now, are rather pricey.

Makers of mixtures of vitamins do two things in general.
1) try to keep the size of the tablet/capsule as small as possible.
2) keep the costs down.

Usually when a mixture occurs, the nice active part of it is the smallest in size. The cheapest (and usually the older form in the mix) is usually the main ingredient.

Thus when you see magnesium (from magnesium oxide, citrate and glycinate) you can count on the majority to be Oxide.

I have called makers on this, and they cannot answer how much of each is in their product typically when a mix is on the label (like with magnesiums).