Why not? With the cost of more than 2k gold to reach level 8 and considering I built many level 5 temples and a level 12, yes, it can be made of gold. Mainly because before reach level 8 you had to pay many times with different values in gold as well.
I'm considering gold because they don't ask for food to build temples. They ask for gold. Also, because I'm considering monetary values and our monetary system is based on gold.
The Taj Mahal was not built with dollars, but it's still the way we are used to calculate its value if we had to build a new one today.