The Glasgow side celebrated their first step back towards the top flight following last summer's liquidation crisis by lifting the Third Division title on Saturday.
The Blackpool assistant manager said: "It's been a really difficult job for Ally. During the transfer window last summer, he wanted five or six players in so he could give the supporters some good football. But, and this is just me reading between the lines, Charles Green never fulfilled his pledge to allow Ally to bring players in."
He added: "Then he let Carlos Bocanegra go out on loan and brought in David Templeton on half the money. So it was cost cutting the whole way and the squad was decimated. The next year or two going forward, that is when you will be able to judge Ally McCoist."
McCoist's men secured the fourth-tier crown with a 24-point winning margin but the manager came under pressure from fans after embarrassing defeats to part-time opponents Stirling, Annan and Peterhead and disappointing cup performances.
Rae - who helped Rangers win the SPL in 2005 - feels Green should have done more to help McCoist rebuild his squad after he was left with just six signed players in the weeks after the club's financial implosion.
McCoist has been criticised for the lack of flair shown by his side and the failure of many of his signings to perform consistently. But Rae says the manager did not have all the necessary tools at his disposal.
"I think that the fact Rangers don't have a scouting network is unbelievable," he said. "If you look at the big clubs, they have scouts worldwide, never mind just in the UK.
"Rangers, to my knowledge, don't have anyone in place at the moment. So there is a lot of work to be done because it just nullifies your chances of bringing in players who are going to succeed."
Former chief scout Neil Murray left the club shortly before Green stepped down as chief executive amid negative publicity surrounding claims by former owner Craig Whyte over his links with the Yorkshireman when his consortium took control. Green denied any wrongdoing.
- Sports & Recreation
- Ally McCoist
- David Templeton
- Carlos Bocanegra