Logix5000 does not have any inherent method I know of for comparing UDT's, aside from element by elelment.
You can hack it I suppose, with the FBC instruction, but my gut feeling is that it would not work properly, (padding) and even if it did, it's only going to say that some bit at some offset is different.
Why do you need to compare UDT's for equality? You must be looking for (in)equality, as if you are trying to do greater then or less then, you already have a certain ordering scheme in mind.