The five gold bars in this mission are hidden at the following locations. 

The house with the Legionnaire's insignia has the first of many gold bars in a 
safe box. All gold bars will be in similar boxes. On your way to the stage's 
second objective, there is a house at a fork in the road with some Russians. 
Clear it out and check the second floor of that house for this gold bar. 
South and west of the Russian missile armory, there should be a small white 
X-mark in make shift pit (this is on the south bank of the river). It is the
same location where Haggard says, "I smell gold!" (the beach camp with several
Russians). 
When destroying the anti-tank guns in the town, there is a building on the east 
half of the town with a red (not blue) "Hotel" sign. The building is defended by
several machinegun nests (mounted and emplaced). You must clear the opposition 
first. Check the second floor. It is one of the few houses you cannot reach the
attic because the box blocks the ladder access. 
After guiding the tanks, you will be told to regroup at the smoke. Instead of 
doing that, go left of the smoke and case the wall. You will see it on a table 
like object.