I'm also a lefty and have handled the 457 MTR rifles. The MTR is set up for a righty, the right side grip is sculpted in a palm swell style but the left side is basically flat where the fingers of the right hand wrap around the pistol grip. The pistol grip area of the stock has a sculpted area for the right hand thumb roll over that's not mirrored on the left side also. On the plus side if you wanted to get creative there's enough wood in the stock to work with if you wanted to modify it for a left handed fit. I like the look of the 457 and 527 MTR rifles but haven't done anything other than look at them. I have an AT-ONE stock that was purchased as an aftermarket stock on a CZ 527 in 204 Ruger, it's pretty much ambidextrous. The stock adjustments are all on the right side of the stock (lefty cheek side) and don't catch my beard at all. The only thing you might want to consider about the AT-ONE stock is it works really well as a set and forget stock but the stocks adjustments are a little bit fussy if your going to be regularly adjusting them.
