Interesting, 4.11 recorded in the syscon...
We already know it has been refurbished at the end of 2009 or beginning of 2010, with 3.15 to 3.21 firmware (right between lasts 2k and firsts 2k1 series). It was probably a mainboard replacement.
But with that 4.11 firmware version recorded in the syscon, I'm feeling at least a second Sony aftermarket intervention between February and Jun 2012. Something lighter like power supply or bluray drive replacement.
(I had a CECHH, without refurbishment data in the NOR, butt with 4.25 recorded in the syscon)
Anyway, it has no influences to use a CFW on it. Just keep in mind your console is a bit special... and has been well maintained.
This one was a very special case with 2 visits to the official repair service

I never heard (or even thought) before about 2 posible ways to update software in it
The first one (the most important) maybe was because the motherboard was connected to a "jig-pin machine", they can replace lot of ID's and all software with that method, also is connected to the online servers to update things like the IDPS
The other refurbishment maybe was made using a jig-usb for an unbrick
-----------------
But... while writing this im imagining maybe it was taken to repair service only 1 time and happened this:
1) The PS3 is sent to repair service, and it have a big problem not related with the motherboard
2) They sends the PS3 to the refurbishment plant for furter analysis to see which parts can be reused
3) They connects the motherboard to the jig-pin machine to "clone" some ID's and the hdd contents to a refurbished console
4) They sends the refurbished console to the owner (the owner doesnt realizes it have a different motherboard of the same model)
5) The original motherboard is kept at the refurbishment plant waiting for some candidate PS3 to adopt it
6) Two years passed
7) A candidate PS3 enters in the service repair, and they takes the motherboard (updated by the jig-pin machine) and upates it again with the usb-jig
...and that motherboard from step 7 is the one that have
@Emeralda in his PS3
...not sure if this theory have some flaw... just speculating and thinking loud
