I'd say your 3-52 barrel is an in service replacement, not an original HRA factory installation. I base this on the absence of a punchmark in the loop of the "P" barrel proofmark. I've examined 5 other HRA barrels with mid 1954-mid 1955 dates and note that HRA was very diligent about stamping a punchmark in the "P" barrel proofmark to indicate an after assembly proof firing. My 10-52 HRA barrel does not have this mark, so I believe that it was installed on another rifle at some point in service. HRA did use LMR barrels as original installations at various times in their production. I have a HRA 475###X receiver with a 11-53 LMR barrel, which I believe to be an original installation. It doesn`t have the punchmark in the `P` either which goes to show that there are rules, but also exceptions to them.
I can`t explain the flaming bomb, rather than the Ordnance crossed cannons stamp. The flaming bomb isn`t normal on Garand components. The Ordnance crossed cannons were used on all WW2 vintage stocks and also on WW2 and later barrels until supplanted by the DAS stamp (eagle over 3 stars). During WW2 production the flaming bomb was stamped on all M1903 Springfield barrels behind the front sight and also on many M1 Carbine barrels depending on the maker, but I`ve never seen it an any Garand barrel that I`ve examined. BTW, the flaming bomb stamp is very indistinct. I`d like to have a closer look at it with a magnifying glass.