Forgot to add that Maruishi, though a rep. builder, is lesser known than many. they made bikes for other Co.s, Shogun is one ex. neither brand was well known to me, having lived in the N.E US for most of my life. EXO is more modern than some Ishi. tubing which were used somewhat later as well. NOT a cheap tubeset.
Your bike seems to be an '87 -on. It could be as late as a '91 or so. I'm not expert on the brand. Fuji was using Ishi on some models here an' there 'till the tube Co. went under. '91s had different type stems so I'm so not sure but I lean early.