They do look familiar but they are not from an 81 SRX or 83 Vmax as I have both sleds and mine don't look like those If they were Yamaha they should have a code stamped in them, the 81 had 8M6 and the 83 had 8U9.see if there is anything like that and maybe you can figure it out.
They look like 81 pipes, but the ends have been cut off and a different end welded on possibly. The ends could have been cut and rotated too that could be why they weld line runs down the middle. If it says 8R9 they are 82 SRX 500 pipes
im not sure what there from but they dont look much like vintage pipes the cones tapered header belly sections ect seem to be too well made to be a vintage pipe.