That springer is an "Old Style" which means it's of 1954-1949, so it could be 52-0r 3. Yet B/C 26 springer can fit any 45-60's frame.
That Junior 24" frame with a matching chain guard to fit a Jr would have S2 wheels so, it could be a Wasp yet in Jr size, unlike 26" size where and extra heavy X mark is found. A Jr may not have that heavy mark B/C 24" Wasp frame with/for S2's would be heavy as is. Yet, but and so, like many Schwinn's it could be any model unless you can find the model's name under the paint.
JR 24" Chain Guard is smaller than a 26" guard. However, depending on the date of its frame, that chain guard may fit most any 24" frame. "May", as if it's a Wasp then in 1955 similar frames were fit as middle weights and S7 wheels but not Wasps. I mean, even a wasp may have same as middle weight, but with S2 wheels and though,, your Jr guard will most likely fit on the newer frames too.
The wheels on the Jr don't look like S2, but I can't tell for sure. . U gonna have a bunch of stuff to buy if these bikes turn out to be what U think they are. Keep getting the house paint off to save original paint and be very carful to reveal any decals or at least fragments of them to too see.
I mean, most all Schwinn bike part are interchangeable so, unless special paint like Phantom, you can stick a chain guard decal of any model and that's what it is.
Oh yeah BTW, in all instances that I have seen, in 24" models, the chain guard decal is also smaller than a 26" I.E. Maximum extra care to expose the decal B/C you may never find one the right size. In the after market retail category, nobody has ever reproduced em for Jr guards like a Wasp would have.