It's absolutely worth the trouble. It will feel very natural to have the hull eject to port. Plus the looks from other shooters will be worth it.
NOW, I know I'm going to start a flame war here, but I was not happy with my lefty 870, which was not as well made as the older guns. My Express (made July 2001) didn't like brass-coated steel-base ammo (Federal, PMC, etc.). It would lock up after firing, and would only release after I slammed the forend forward and backward to jar it loose. I noticed other QA issues that Big Green didn't see as worth fixing, so I sold it.
I replaced it with a LH Fabarm H368 auto bought for $550 new, and I've never been happier.