Questions, New (to me) 90 Allanté

Just picked up a 90 model and it runs great. The only things that are irking me are in the driver's module. These are some of the messages displayed:

Change Oil (Oil was just changed)
Service Engine Soon
Traction Disabled
ABS Disabled

And the radio hums for awhile, then plays thru one speaker (passenger side.)

Also, I thought that for 1990 it was supposed to have the Bose sound system, but this one has the AC Delco "Symphony Surround" system. Does this mean the original was possibly replaced at one time?

Thank you in advance.