Target stocks, screw adjustable for LOP--must they be pinned?

[10X 3,296]

OK, so consider a target stock for an AR, with adjustment screws for length of pull and comb height.  The two examples I'm familiar with are: 

 

http://tacstar.com/home/ar15stock.php

 

and 

 

http://www.opticsplanet.com/magpul-ar15-precision-rifle-sniper-stock.html

 

Neither is quickly adjustable, both have a screw that lets the length of the stock be tuned by about 1" to optimize length of pull.

 

Are these likely to fall under the 'telescoping stock' prohibition, and so be required to be pinned?

 

Bonus points if anyone has either of these and can tell me if they like it (or can recommend a target stock they like better).

 

Thanks.

[T Bill 649]

They are not considered telescopic stocks and are GTG.  They are adjustable.  The Magpul PRS is a very popular target stock.