The parts on the Lamberts we brought into the bike shop I worked in---the hubs, cranks, brake calipers, brake levers, maybe other stuff I can't remember---were produced by Lambert in house. The bolt pattern for the chainrings was based on the Stronglight 49 crank, if I remember the number correctly, but the crank wasn't manufactured by T.A.
It's easy to tell a Lambert crank arm from a T.A. crank arm---the Lambert design used a nontapered bottom bracket spindle that depended on a big washer between the crank and spindle to keep the crank's spindle hole from deforming. It didn't work very well, which is one reason you see Lambert cranksets available for sale from time to time.
My last dealings with Lambert bikes were in 1976 or so. It's possible that T.A. supplied cranksets after that time. But if the cranksets you're talking about have nontapered surfaces in the spindle interface hole, they aren't T.A.