There is next to nothing for this shotgun as far as plastic or "tactical" aftermarket accessories. Gunparts has a military style stock that has a shortened length of pull and that is all I have seen form this style of shotgun.
They do have the commercial replacement stocks on hand, last time I checked. Standard length of pull.
Some of the 67's that are patterned after the older model 30 savage have non removable barrels, or solid frames if you will, meaning that the barrel is screwed into the reciever.
I have one of these older guns in the form of a Westpoint Model 167 or 67 h. I can't remember which and this old shotgun has killed a slew of deer in its previous owners possesion and I got it in a trade, cleaned it up, cold blued it real good and now use it for a bump in the night alternative weapon among other guns that I have. The only "tactical" addition is a barrel amputated to 20 inched for social work and slug shooting by the previous owner.
You will probably going to have to relegate your shotgun to another use or sell it and get a Remington or a Mossberg. I would suggest a Pardner Protector in black plastic as these are good to go outa the box.
To conclude, the gun you have is a decent ,field grade shotgun and should do well in that realm. It seems from your post that you would like to build up a "tactical" shotgun and the 67h is not a very good choice in that regard due to the aforementioned reasons.