Dembele has been named Ladbrokes Premiership Player of the Month for February and is currently on a prolific run of form which has seen him score 12 goals in his last six games for Celtic.
The 20-year-old Frenchman, signed from Fulham for just £500,000 last summer, has netted 32 times in total – including five in three Old Firm fixtures – so far this season.
Dembele has been consistently linked with a plethora of leading English Premier League and European clubs over the past few months with many observers, including Celtic manager Brendan Rodgers, valuing him in the £30-£40 million bracket.
But former Rangers striker and manager McCoist, who claimed an all-time record tally of 27 goals in Old Firm matches during his playing career, has dismissed that figure as unrealistic.
“Moussa Dembele isn’t a £30m or £40m player,” said McCoist. “If [Celtic chief executive] Peter Lawwell gets that amount, then good on him. There’s a man doing his job very well!
“Dembele might develop into a player of that value. I like him a lot, he can finish. He’s got a good physical presence and movement. But realistically he’s not £30m, £40m.
“He’s certainly the most valuable player in the country. He’s young and will naturally progress. He’ll take part in the game more. He’s very much a finisher and concentrates on his finishing which is good but other parts of his game will develop.
“Celtic will certainly cash in on him, there’s no doubt about that, but I’m not in the £30m or £40m brigade if you can spare me that.”
McCoist has admiration for Dembele’s big-game temperament which has been evidenced both in the Champions League and Old Firm games this season.
Dembele scored a hat-trick on his Old Firm debut, when Celtic thumped Rangers 5-1 at Parkhead last September, then netted the only goal of the Betfred Cup semi-final between the sides at Hampden the following month.
He then scored the equaliser when Celtic came from behind to win 2-1 at Ibrox in the second Premiership meeting of the old rivals on Hogmanay. Dembele is hotly tipped to extend that streak when the sides meet again at Celtic Park on Sunday.
“It says a lot about his mentality that he’s scored in every Old Firm game so far,” added McCoist. “It’s difficult to maintain that level of quality of finishing, regardless of the opposition.
“If you look at his goals – particularly in Old Firm games – they’ve all been different. Headers from corners, turning Philippe Senderos in the first game at Parkhead. He’s not a one-trick pony and I like that about him.”