The value of your console lies in the data you can recover from it; preserving that data is only going to ruin the console if you can't read the guide and you brick it. As mentioned there is an archive of DEX OFW, it's from the same place the REBUG CFW I linked you. You can take note of the firmware it was on from system settings, and grab that once you're done grabbing the eid_root_key. The process is so straightforward, I can guarantee you nothing will go wrong as long as you follow it to a T.
If you want to just have the test kit for show, so be it. Your console, you do what you want. But just know that you could very well be sitting on valuable data that would be of major benefit for researches, modders and gaming fans alike, and unfortunately, dumping the EID with CFW is the most accessible way to know this for sure after you dump the hard drive. I own a few PS3 kits that had deleted prototypes I was able to recover, I've donated/shared some for release in the past.
I sincerely hope you consider dumping the kit at some point, as even just some closure on whether or not you have data would ease concerns of what the kit's got tucked away. Besides, anyone can find a DECH or DECR unit, many of these have sold, publicly or privately, in the past half a decade. Not everybody can find the same history underneath though.
Apologies for the massive write-up here, you're not in trouble and ultimately it is your decision, but I think you'd be surprised and intrigued by what's been discovered through these dumping methods. Look at the Terareleases here if you want examples
