No, by default the 8051 is not available for Flowcode. This question was asked on the AVR and MicroChip forums and the developers didn't state it's compatible with. However, the version of the Flowcode has been updated up to version 6 and it's possible it supports the 8051. I recommend downloading the application from the official website. If you have the 8051 chip, connect it to the PC and then attempt a device discovery in Flowcode.