Well, I decided to dress up my SAR-8, the Greek HK-91 clone, with a new set of green furniture.  Unfortunately, the old/new buttstocks have some differences I don't understand.

(1)  On the OLD buttstock, the buttpad was removed via a screw, and a long bolt went from back to front to hold a metal piece in the front of the stock (see pic).  The new green stock does not appear to have a removeable buttpad.  Is this correct?  Is the long bolt not needed?

(2) The new stock has a concentric tube that slides freely from the front of the stock down into the stock.  Since there appears to be nothing holding it in place, it would flop back and forth with the stock installed, making noise and serving no apparent purpose.  What's the deal here?

Any help appreciated.

Easy one.  

First off, remove the butt pad on the new stock by using a towel and insert the toweled butt pad in a vise, then rocking the pad out of the stock. The butt pad is attached to the buttpad with spring clips that spreed open over the two cross rods in the back of the stock.

Or since the buffer is not in the stock, use a dowel down the buffer void and press the butt pad out the back(between the two butt stock rods).


 
Inside the stock will be a small plastic sleeve{the floppy part you discribed}(you will need to order the correct short screw, The long one will not work) to attach the buffer to the stock.  The order of install is back plate to butt stock, face load the buffer, then tighten the two receiver side buffer screws, then tighten the newly ordered back buffer screw in the butt stock (using the plastic sleeve{floppy part}), then snap the butt pad back on to finish the install.



www.aa-ok.com/G3_%26_91_Buttstock_Parts/g3buttstockparts.htm

Dano, thanks for the info.  Got the buttpad off and the parts ordered, now all I need to do is wait.