False. It's stated in the Manga that Freeza is much stronger than his father, who is not ever revealed to actually have any other forms. We only insinuate that because his model looks similar to Freeza's second form, but this is pure speculation.
It's also disproved by the fact that he had ample time to transform against Trunks, but didn't, and stalled for time other than to transform. If Cold had another form, he would have transformed, no question, his life was on the line.