I thought so too, but in reality the process was improved for mass production by use of large tanks and steam chests — certainly slower than a modern bluing process, but still improved enough to allow for mass production of tens of thousands of rifles or rearsenaled finishes annually.
You can actually use an accelerated rust bluing with a humidity box and steam pipe in your garage to conserve these firearms — same as when rearsenaled.
I’d recommend taking a rifle out of the stock for cleaning and inspection after several years in — a lot of deterioration can be going on under the wood if not cared for. While it’s out, it’s a good idea to do a heated ultrasonic cleaning if needed. From there apply your preferred protection — long term or active use.