Road trip to see the KB-50J Superfortress

MacDill air force base is 12 miles south of my house. I drove down there this morning to visit a small park on the base where they have three aircraft on display. The airman standing guard at the front gate looked at me and said: "Nice car, sir!". God bless and protect our airmen. The airplane that I had always assumed was a B-29 Superfortress turned out to be a post-war B-50. A sign explained that a B-50 was a post WWII modification that had a bigger body and 50% more power than a B-29 and that a B-50 was the first airplane to fly around the world non-stop. The KB-50D on display was built in 1947 and retired on October 1963. It was still serving on active duty when my Falcon was a new car.
See: http://www.johnweeks.com/b50/b50usafmKB.html (This says that the plane was a 50J, but the sign at MacDill says it is a 50D. I can't say what the difference is.)

A pair of fine pieces of American machinery:
Attachment 2929

The KB-50D was upgraded with two jet engines:
Attachment 2927

A 1963 Falcon and a F-16A Falcon:
Attachment 2928

Last week I flew out of Madison Wisconsin. While waiting at the gate I was shocked to see a B-29 land. It was amazing. I think it is likely on it's way to the EAA Fly-in in Oshkosh.

I have never heard about the modified rig you saw. Pretty cool.

KB50J from wiki:
"Conversions to air to air refueling tankers with improved performance from two extra General Electric J47 turbojets under the outer wings, 112 converted from B-50D, TB-50D, RB-50E, RB-50F and RB-50G aircraft."

So I guess they are both right. Since you picture shows the installed turbojets that would indicate it has finished the conversion and is now the KB 50J... unless it is just a mockup.