Do not use the formerly registered (canceled for failure to file a 6th year Decl of Use under Sect. 8), TRIOPOLY and you should be okay if your design is original. An IP or copyright attorney can check to see if there are registered copyrights on such mats. There might be a copyright existing but not registered that might cause problems, but if you keep this pretty generic or different and original you should be fine. Put your own brand name on it and register that brand name. Also, if you have original elements in your mat, you should apply for registration of a copyright on the original artwork for your mat.
See an Illinois IP lawyer for help on that, as there are additional protections under IL state law that may be appropriate for you.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
Most copyrights from that era are now 'public domain,' but it is hard to tell without an investigation. Do any search engines turn up such game mats? If not most likely you will be ok, especially if you carefully document all your efforts to find any possible current copyright claims on the web and at copyright.gov.
Licensed in Maryland with offices in Maryland and Oregon. Information here is general, does not create a lawyer-client relationship, and is not a substitute for consulting with an experienced attorney on the specifics of your situation.