As long as you check it when it is fully hot, in park and running and on a level surface you will have a good read on the dipstick. Wipe it on a clean WHITE towel to check the color. Should be nice and red and not smell burnt.
My rule is- When I get a car that I know none of the maint. history on I change every fluid and filter, regardless of what the seller has "said" they changed. Then I know what has been done and what hasn't. At that mileage I would NOT flush the trans, just do a simple pan drop, change the filter and refill w/ Dex VI and call it a day. If you want to help it live longer maybe install a shift kit and add a quart of Lucas to it when refilling.
