IM6 rods are fantastic rods. Loomis are all I own now. Had a number of Winston rods over the decades. Good luck in finding one. It took me over a year to find one on the big auction site to replace one I broke.
Edited to add to allow a further understanding of your search (something I found on the internet):
1987-1988/89 Winston first production IM6 w/Trophy cup logo (Loomis blanks) #12,000- roughly #15,000 – both IM6 and Trophy cup logo on rod- Winston's first trial run at introducing rods made from the IM6 graphite composite, which were produced by G. Loomis forever thereafter until Winston began “rolling” their own blanks in late 1994. During the first Loomis IM6 production, they still labeled the rods with both IM6 and the Trophy cup- trying to win customers with new technology and please the old customers not wanting to lose their trophy cup status.
1989-1994/95 Winston IM6 (Loomis blanks) - early roughly #15,000 –#25000 / later #25,000 through roughly #43,500- IM6 on the rod- were all Loomis blanks- Winston designed specs. All rods inscribed as IM6 beginning with serial # of 43500 were actually made from the new WT graphite composite (just another blend of IM6 w/ same exact tapers) and came off Winston’s production line in 1995 and beyond. Winston’s lifetime warranty also began with serial #43500. Winston did not change the “IM6″ moniker on the rods until 2001 when they officially introduced the WT product line. Please note below exceptions.
1995-2001 Winston IM6 (own blanks) roughly #43,500- +/- #80,000 IM6 on the rod- even though #43,500 is known as the end of Loomis made blanks, and the beginning of producing rods from their own new WT graphite composite, Winston also still produced rods from their remaining inventory of Loomis IM6 blanks. Some Loomis blank rods of various rarer model configurations/ lesser produced specialty weights, etc. can be found with serial numbers as late as # 75,000 or even higher (produced with leftover blanks years later)- some Loomis blank rods during this period weren’t labeled at all (no IM6 and no WT on the rod-just the length and weight). Truly Winston's blanks and Loomis blanks were so similar, not only in exact same specs, but in quality, lay-up, visually, they are virtually almost impossible to tell apart. This was obviously done by design and planned to be that way.
2001+ Winston WT (own blanks) roughly #80,000 + WT on the rod
Maybe this will help...