I do not think it is paint, it is more like a decal. My truck has something similar going on with the stripes, but they are for sure decals, as some portions have peeled away significantly. Nissan probably had a few different decal packages; it was the 80's, after all!
I haven't seen a write up on here, but dash removal is in the FSM. The cluster is pretty easy to get out though. There are two screws facing upwards on the upper part of the black cluster bezel, and two clips on the bottom that hold it in; pull straight out and take your time so you don't break them. Under the bezel there are like four screws that hold the cluster in place. Disconnect all the plugs (don't bother marking as they are unique to each spot, and disconnect the speedo cable (see this for what it looks like). The job is easier when you remove the steering column cover as well.
Update: Block heater is installed. The PO had one of those expandable plugs in there, so taking it out was actually relatively easy. Just a couple turns and a needle nose pliers, without having to remove the manifold or anything. The heater went in a little tight, but overall it was a fairly easy install. I'll throw some pictures and a part number up later.
Does anyone have a Z24 out of their truck and could measure the diameter of the left rear freeze plug? I'm looking at this block heater. Amazon says it fits, but obviously doesn't tell me which freeze plug it would fit in. I say the left rear because that is the one on my truck that is having some leaking issues, and if I can replace that one with a block heater, it would kill two birds with one stone. If you happen to have the freeze plug off, I would also like to know the depth from the edge of the hole to the cylinder wall, because it would suck if the element was too long.
I think the 2nd one is the easier install but you bring up a good point of the radiator.... I would think the one in the freeze plug would be better since it heats the coolant in the block first before the heat eventually gets out to the radiator...
My thoughts exactly. What's the point of heating coolant outside if the thermostat would be closed and not preventing flow? I do not think it would help with cold starts either.
Just a fun update: It was -15 degrees fahrenheit in Minnesota this morning, and I had to get home from a friends house. I do not think this truck has ever seen temperatures this cold in it's life (Cali truck), and it sure was not happy about it, but it did start without too much issue. Couple of pumps, turned the key and after a few wubs it started up. My biggest concern was actually the transmission oil because the transmission lever was very stiff as well as the clutch. After letting the oil warm up I took it very gently and just kept it in fourth gear the whole way home. The variety of conditions that this truck can handle considering its age amazes me. A question for the Canadians on the forum: Do any of you run those stick on oil pan heaters to keep the engine oil warm? I've been thinking about picking one up because as fun as it is to drive in these conditions, I know it's hard on engine components when the oil is that cold.