Newbie here. I'm looking at an M75 Varmint in 204 Ruger to keep my L461 company. Looks brand spanking NIB with one oddity. The end of the barrel is threaded and capped. I haven't seen any other pics of an M75 with a threaded end. Was this a factory option or would it have been done after market? I'm assuming that if it's after market work it would have a negative impact on value. Thanks for the help.