Yes, the 8344 is a member of the RUPI-44 family.
The 8044AH includes Factory Mask PROM
8344AH for use with External Program Memory
8744H includes EPROM

Chapter 11 through 15 of the 1988 version of Intel Embedded
Controller Handbook Volume I 8-Bit gives complete detail
regarding this part.

It basically has a Serial Interface Unit (SIU) that is more advanced
(with lots of bells and whistles) than the usual 8051 series uC.
Otherwise it is totally based on the 8051 series.

If it's of any interest, this book covers the following uC's
MCS-48 (8048/8049)
MCS-51 (8051)
RUPI-44
MCS-80/85 (8080 * 8085)

Best of luck,
Josh