Also, Remington refined the shape of the lifter over the years to make it more reliable. They put a shim spacer in between the stock and the receiver sometime in the 60's to solve this.
First, you're going to see a lot of early Wingmasters with cracked or chipped buttstocks near the wrist. The early Wingmasters were great.but there are some differences. OK, I just have to weigh in here, having owned dozens of Wingmasters over the years.