Original set of spark plugs??

Hello guys! This is my first post on this forum, and I hope some of you will find it interesting.
I have a 1999 4Runner Limited, 3.4 liter, 4WD which we purchased new in the Chicago area. It now has 192k miles logged. Yesterday, I replaced the original spark plugs with genuine Toyota Denso K16TTR plugs, and when the original plugs were removed, I got quite a surprise! The old plugs were comprised of 3 Denso K16TR11 plugs, and 3 NGK BKR5EKB??

I had it serviced at various service facilities, mostly Toyota dealerships, so I can only believe the plugs were installed at the factory in Japan, but can't believe that's what happened. Could I be the only 1999 Limited owner that has this combination of spark plugs?? I have my doubts!

The good news is both brands seemed to have similar wear on their electrodes, but one of the NGKs' ceramic was more discolored than the Densos. Hopefully, the picture explains this better.

 

My 2nd gen 4.0 Tacoma had the same configuration of spark plugs from the factory. I forgot the serial numbers but there were definitely 3 NGK’s and 3 Denso’s. And I believe I replaced them all with the NGKs. I think it’s pretty common...could be wrong though. Your gas mileage must have been terrible with 20 years old/200k spark plugs?.?.

 

Surprisingly the gas mileage stayed in the normal range of 13 city-18 highway. I consider that pretty good but will keep tracking mileage, hoping to see some improvement.

 

I got mine to 200k miles. Looked similar but worse than yours. Mine were all the same...forgot which brand. I replaced with TOYOTA plugs and plan on getting another 200k!