While a square is a rectangle, rectangular paddles are not square.
You don’t see this waffle iron too frequently, but yours does need some TLC to say the least. If you want to see what people are willing to pay, you could put a reserve auction up on ebay. That is probably where you would get the best price estimate. If you have a copy of the Red Book, take a look at page 74. I believe there is a photo of one like yours there. Restored, it still may bring the estimate listed, which is slightly higher than the $200 limit mentioned earlier.
This one would be a real project to restore.