Yes, there was a 560. It was exactly the same as 550, but introduces 2 months later.

From MacTracker

"The LC 550 replaced the LC 520 in February 1994. It was identical to the 520, but had a 33 MHz 68030 processor. All other specs are the same. It sold for $1,200 U.S. and was also sold as the Performa 550, and 560."