This, exactly. This is what you must do if you have to take your firearm to a store to try it in a holster.
So a few weeks ago I stopped into one of our local shops, no intention of buying anything, just looking. Found something that really interested me and bought it. Now I don't have a holster to fit it, but it's approx. the same size as the piece I'm carrying. Ask the clerk if it's OK to check it out for fit, of course I need to remove my sidearm from the holster which is loaded with one in the tube, I inform the sales clerk of this, he says go ahead, no problem. Loaded pistol lays on the counter all the while holster is being tried. So now I'm an idiot? Don't think so, you may, but I don't, and neither does the sales clerk nor the shop manager who was standing right there, nor the city officer who was right behind me.
BTW, my holster did not fit and I bought one that did, all the while the shop manager swept most everyone there trying to find one that did fit. The gun is not going to go off all by itself, that is a fact, never going to happen.
Once again, temper your safety with common sense. I realize this is in extremely short supply today, about like .22 rimfire ammo.