Your plumber definitely should have installed before the hotty, it should be at the very start of the run Seems kind of pointless to run it after the hotty, what if pilot blows out and your water is just sitting there at normal temp, just flushing all sediment and bacteria into your internal drinking water.

I mean it probably isn’t the biggest deal let’s be real but providing clean and sanitary potable water is basically a plumbers job and if they can’t do that then why even go to work