Exactly. Simes also documented that on his blog.
My lines came from Drags as well, and the larger pipe feeds the rockers, just like yours. Should be the other way around. If you can solder pipe connections, it is quite simple to exchange the fittings one for the other. But, if you don't, the worst that can happen are oil leaks from the rocker boxes or some oil getting into the valves and you puffing some smoke. It's not critical, but when you have a chance, why not? A job I had planned for next winter, but will probably do it now while I'm waiting to get the bottom end sorted out….
Regarding that knocking of yours - if you don't find anything obvious through the primary inspection hole, then you'll have to get that primary cover off (and yes, also the whole clutch has to come out...). Then turn the engine with a socket wrench on one of the drive side crank nuts, and see if the noise is still there. And if so, you'll just have to keep on disassembling part by part until you find where the knocking comes from…