Between June 1943 and Sept. 1943 Inland sent about 12,000 receivers to Underwood in sets of 2000 to 4000 receivers. This serial number falls in that same time frame. While it looks odd the way the line out looks it could have been someone new just starting out using the machine to do the line outs or maybe the machine was broken at the time and something else used. It looks to be worn about the same as the rest of the stampings on it. With the damage on it the demand for it is going to be very low to say the least but I would bet if assembled into a complete carbine even with the holes in it that it would function properly.