Yes, early oil lines definitely rubber coated over a smooth smooth fabric.
You can see really good pics of 232's smooth lines in the "Restoration/Technical Support" part of the website. They appear same as yours and are same as Andy Dixon's 175 oil lines.
Interesting, on the chrome appearing finishes of the four 6mm lower fender brace "8" bolts. Who knows when these bolts could have been plated, i.e., from the factory -or- later on ? The really good part on your bike is we are seeing for the first time details of the earliest vin yet given to public view. The down side, is, we have no vin close to 97 to compare it to. It would be nice if members with vins closest to yours would participate in this discussion. The three 8mm upper triple clamp bolts i have seen on any sandcast are plain head, chrome plated.
I can say, 232 had all it's bolts (all early 8's) except the two 8mm pinch bolts for the center stand pivot pipe. There were no chromed "8" bolts. On another note, the special bolts fixing brake line banjos were chrome plated on the early bikes, not zinc as per later.
Speaking of "8" bolts........ Are your 4 special shouldered 10mm bolts fixing rear sprocket to the carrier, "8" type ?
The 69/4 parts book shows a the typical Phillips fillister head screw fixing the ends of the 2 gauge rings together. I don't know how i could debate the "8" bolt fixing your clamps together is not correct, but it is extraordinary to the convention of experience and literature. Do you have a copy of the 69/4 parts book ? 69/7 book was the next printing after 69/4.
I have an incredibly clear and detailed color factory photograph (enlarged to 16x20 from a 3x4 (commercial size) slide transparency) of which appears obviously to be an early production (grey horn) red sandcast. Also, numerous small b&w pics (as nowhere else) seen in the 69.6 "Set Up and Pre-Delivery Instruction Manual." As well as numerous pictures from 24 different magazines from March 69-Apr.70. When i "took delivery" of 232, i studied these pictures very closely, searching to compare what i found on 232 and to discover "what i thought" could be considered correct and original to early prod.bikes. I don't remember seeing anywhere an "8" hex head bolt holding the instrument clamping rings together. Again, in these magazines, these are pictures of probably (only) no more than 2 different early production bikes loaned to magazines for testing and evaluation. One was red and one was blue-green, of which the latter was more photographed in the magazines than the former. The Apr.70 Cycle Guide Magazine documents the blue-green bike was engined by vin E24 and also notes in the road test article the Cycle Guide testers did not have access to the bike until after other magazines had completed their testing of the bike. This road test was one of the better (b&w) photograped tests a well as had the machine shown on the back cover in full color, as noted on our SOOC home page. In contrast to all the other machines to roll off the assembly line, we don't know what parts they were fitted with. So, like i said earlier, not sure how i could otherwise debate an "8" head bolt fixing those rings together is not correct.
Whew. i don't know what i wrote is that helpful.
When it comes down to it, all we can do is share our first hand observations, compare to literature and make assumptions.
And so, again, "THANK YOU " Mark for sharing your #97 with us !