I am beginning to question the conventional thinking that Marlin did not start making their Model 90 O/U with an open space betweed the barrels until 1949 or '50. I have a Marlin Model 90, 16 ga. serial no. D184 (made in 1947) that has a web between the barrels. I just bought a Model 90, 12 ga. serial no. D1477, that is open between the barrels. I have two other Model 90's, a 12 ga. made in 1950 and a 20 ga. made in 1954 that are open between the barrels. Anyone else have a Marlin Model 90 having a serial no. from Axxx through Exxx that is open between the barrels? Just curious.