The mag tube is the only part I have been able to find. All I need now is the butt plate and the proper rear sight. Any ideas as to what other models of marlins shared the same two parts.
From "Old Gunsights" by Nick Stroebel, in part
Standard
Lyman no. 3 ivory bead front sight, and a Marlin Rocky mountain Rear Sight
Optional front and rear
Same as those for the Model 20 Rifle
The model 20 list quite a few sights
Standard is the same as above
Optional front
Marlin rocky mountain front sight
Marlin .22 Caliber front sight
Beech combination front sight
Marlin globe front sight
Lyman no. 4 ivory hunting sight
Lyman no. 5 combination front sight
Lyman no. 21 ivory bead "Jack" front sight
Optional Rear
Marlin rocky mountain rear sight (small size)
Marlin .22 caliber rear sight
Marlin gallery (tang) peep sight
Marlin no. 32 windgauge rear sight
Marlin improved graduated (tang) peep sight
Lyman no. 1 combination tang sight
Lyman no. 2 tang sight
Lyman no. 47 windgauge stem
Lyman no. 52 windgauge tang sight
Lyman no. 6 folding rear sight
So, you've got lots to choose from