Sweet seems like you all set for natural gas!
Remove the cap, dope the theads, and install a reducer elbow 1/2 X 3/8 in. Short 3/8 nipple to a Tejas 3/8 QD ball valve #104007@ $39.95. No gas will flow without the mating QD plugged in. In other words a child or some ass hat can't inadvertantly vent gas accidentally to dick with your gas bill. You need one #401207 3/8 male plug QD @ $12.95 and one # 104001 3/8" QD Socket @ $24.95. I got a 12 Ft hose and am glad I did! (I was thinking shorter)#100484 @$44.95
For brass ( SAE 45 degree Flare Fittings ) You need two male adapters 3/8 Flare X 3/8 Male NPT which you can get @ Lowe's or Home Depot. The tuff part which are essential to connect to the Blichmann orifice valve which is a 3/8 male flare, I got from
http://www.fittingsandmore are one #10-136, a 3/8 female flare Union, and last but not least get four Copper Gaskets #10-087 3/8 " to use on all 3/8 flare connections and have a couple of spares. Copper forms an excellent seal! Their shipping is a little slow so order soon.
I sized down to your 3/8 ID which should be fine@ 60,000 BTU
I dealt with Cheyenne @ Tejas who was very helpful @ phone # 713-222-0077