Enforcing the magazine capacity ban can be tricky business. Obviously, LEO magazines are not permitted nor are non-ban magazines with post 94 date codes. I have many "pre-ban" USGI 30's which have absolutely no markings, with the exception of the floorplate. There are absolutely no date codes to denote date of manufacture. You could possibly prove date of manufacture by the markings on the floor plate. You could research who had the contract and at what time. Also some of the manufactures went by different names during the ban, so you could show that magazines marked with the old name are pre-ban. I hate magazine capacity restrictions as they are impossibly easy to circumvent and dont restrict the capacity of a weapon. It just confounds people who own P99's and newer weapons who want high capacity magazines. It also gives idiot gun dealers the cause to charge 35.00 for a Cooper/Sanchez magazine because its in the bag. I have seen "pre-ban" G17 magazines for 80.00 and non-LEO marked Mini 14 20's for 140.00. Insantiy. I would be weary about owning non-marked magazines, unless I could prove date of manufacuture by the companies name/contract date. Illegal magazines are illegal magazines, so if they don't have a date stamping or I couldn't prove they were legal, id likely not own them. If you insist on having non-marked magazines which you "believe" are pre-ban, why not own non-LEO marked D&H or similar for a fraction of the price. If you are going to break the law, which you shouldnt, you might as well do it with good magazines.