Check eBay for the guard for the Huffy Flaming Stack guard, they pop up there in the $150-175 range for nice guards without rust.
For the Murray headbadge, you're just missing the reflector in the middle where the hole is. I think that reflector is the same as the ones on vintage bicycle...
Here is the eBay auction I saw for the frame caps:
https://www.ebay.com/itm/70-1-1-4-OD-SNAP-IN-METAL-HOLE-SPRING-CAP-TUBING-END-INSERT-PLUG-1-1-8-NICKEL-/362206107736
This guys doesn't seem to have them any longer, but I'm sure other sellers do.
It sure is! Very neat save on that one. Those frame caps are available in eBay, they are for cars I think, let me see if I can find the auction with them. They are cheap, like $1.
What a good friend indeed! I agree with Jaxon, it is a 1967 frame with the carryover 1966 shifter and parts. I bet that was an early production 1967 bike. Very cool score! It is very clean and other than the pedals and maybe the front tire it looks to have all the original parts.
VERY cool Mark II Eliminator! That is a rare one, might be a non-Murray badge too? I think the 20 x 20 had a 1 3/8 front tire, your bike has a 1.75. Maybe it was a build for a department store and could be one of a kind. Congrats!