Both SEM and TEM. The thin layer of gold prevents the sample from charging. That would work if the gold is sputtered.
What bothers me with this question is the word "dipping". This bothers me a bit:
SPI-Mark™ Colloidal Gold Reagents - Selection of the Right Conjugate - SPI Supplies
That states that you need something else besides gold to make it stick.
When you use the term DIP, I would probably change my answer to SEM only.
What do you think?
SEM's I've used and fixed. TEM's I have not.