The top picture is of the R390/R-390A Filter with the "N" style package 2.75" in length. These receivers have four of these type of filters -- 2, 4, 8 and 16KHZ. Interestingly these receivers have 0.1 and 1 kHz bandpass positions but these filters positions are discrete (RLC) filters not mechanical or crystal.

The bottom two pictures show the "K" style filter used in the 51S-1 receiver. This package is a soldier in unit. The X500K8Q 800 indicates that this is a 800 HZ crystal filter designed to work in 500 kHz IF.