I am a lefty two. There are two parts of the gun that MAY need to be ambidextrous:
1. mag release.
2. fire selector.
Mag release is almost easy to fix, just get this and replace it yourself:
http://shop.ehobbyasia.com/gandp-kac...l#.WJifDhsrLDc
or
http://airsoftdepot.ca/catalog/produ...oducts_id=4286
Unless you are running high-cap mags, I see no reason why you would need to change mags so often. At least it has not caused me any trouble, I just retreat replace and push again.
For fire selector it will get tricky, the part needed is more or less rare to find in Toronto:
http://www.evike.com/products/55965/
Most games run on semi-auto which means you won't need to switch this too often. If your gun comes with it, awesome, if not, whatever.