I bought an extremely rare 1903 Carl Zeiss Jena Universal Palmos camera very, very inexpensively on eBay. The previous owner had removed the original 6x9 springs and ground glass and attached a 5x7 B&J back in their place with four brass cup hooks (and I mean the back...grey wood and everything else on top of the original camera's back!). The person selling it on eBay read the B&J on the back lid and described it as a B&J. No one bid on it but me, since the old black camera did not look at all like a grey B&J! I was delighted to have it for $30.00, and removed the B&J back. Unfortunately the original seat for the 9x12 springs and gg had been modified to take the 5x7 back, so they were not restorable. Instead I filled the extra space in with hardwood and adapted a 4x5 back on it, making it as close as I could to the original. The camera is now usable.