Topping off with water after kegging?

Good morning all -

I brewed a blonde a couple weeks ago...supposed to have been 1.041 @ 5 gallons. I got more like 1.045 @ 4.75 gallons. I didn't do anything before fermentation when I noticed this...I just capped it and let it do its thing. Now that it's done, I'm thinking I'd rather it be closer to what I wanted it to be.

My question is, when I keg this, if I add a half gallon of water or so...would it be the same as topping off before fermentation? Or should I just leave it as is?

Thanks

Once the beer is done fermenting, let it be what it is.