This glass is called a "Bar Glass" in the Derby Glass World. Most with dates are between 1963 thru 1983. Some w/o dates, like this one. Some are nice and some years have more than one BG issued.I cannot estimate the year. Many glasses with KY Derby on them were made but are not Official KD issues, hence they became known as "Bar Glasses".
Please send me your email as you may have some KD glasses I need. My number is in the Roster.
Happy Hunting all Bob S.