Some 747-200/300 (passenger aircraft) had 2 bunks for cockpit crewmembers -
These were located to the aft portion of cockpit, on LH side -
Same arrangement for 747-400 airplanes -
In addition, in 747-400, there is a cabin crew rest area ABOVE the rear galley -
Access through a door and stairs near L-5 and R-5 area -
It is generally configured with 8 bunks and 2 seats -
In the 747-200/300 I flew - we blocked 2 rows of passenger seats in Cabin E -
Behind a curtain for privacy "do not disturb - crew rest"
On cargo 747 airplanes, the upper deck is a flight crew rest area -
Often equipped with 3 bunks and some 4 or 6 reclining old 1st class seats -
Back of the aircraft underneath the rear galley.
Perhaps you should ask the Stewardess to show you where they are.She wont wonder at all why you would want to know this.