Eric at Topgun has done a fine job putting tritium sights in several HKs for me. Don't know if he's at all familiar with the LEM kits but they're super easy. Fits one tool me an hour perhaps, second maybe 30 minutes, last 15 tops. If you want shoot me a pm and I'd be willing to lend a hand.
I don't know of any actual HK armorer's around the StL metro area.
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