I can't remember who made those five spoke magnesium mags. I used to have a pair that I converted into a freewheel. ISTR they had a rep for exploding or catching fire or something, which sounds rather outlandish. Mine lasted quite a while and were retired without incident. Sadly, I don't know what happened to them.
I think those mags associated with Mongoose BMX bikes were Motomags, those really cool (and heavy) five spoke cast aluminum wheels with a small "X" spokes between the five spokes.
My recollection of Lester mags were that they were a somewhat less desirable also-ran in the market, often appearing on lesser BMX bikes. Cast aluminum like Motomags, and available in different colors and patterns, they sure did look nice. I think they were introduced on the tail end of an era, when mags were no longer taken seriously as BMX gear. It's a pity they aren't more common. They might fetch a nice price on ebay. That old school BMX stuff seems to be in demand.