If char had the gouf during the first encounter, and went down with the other zaku pilots, he would've easily destroyed the gundam. Amuro at this point has no experience, and would struggle uniquely against the gouf.
I think the gouf is alot more powerful at combat than the zaku. The zaku ii really can't do much close range besides kick. It has the heat hawk, but the heathawk sucks. The gouf has finger cannons, heat whip, and a sword, giving it three seperate ways to fight the gundam at close range.
The only thing countering this theory is 0079 ramba ral loses, but thats against a much more experienced amuro.

In conclusion the red zaku ii, was a terrible machine, and only used by char, because there was nothing better for space combat at the time. If he even had a high mobility modification he might've won their first fight. Char would be better focusing on close range with an ace suit, like the gouf. With no gundam, gqux happens as usual, but without gqux, gelgoog, or gfred. Easy zeon victory.