Yes, the one at the tank is actually a silicon ring to allow for expansion of the pipe. The cooler has the only flare fittings and I'm taking my chances with a single flare as I don't have double flare dies. All it can do is leak and then I'll buy the dies.
The cooler I have is 37 degree not 45 so I turned a 37 degree (74 combined instead of 90) and use that to press the correct angle. I imagine if one took a 45 degree copper tube flare, heated it red hot and quenched it it would probably be soft enough to be reformed to 37 degrees by the fitting nut.