Is there a formula I can use to check if the value in another cell is an
actual value or a formula that generates a value?

In column "E", I have about 1,000 rows of values. Some of these values
have been typed in and some have a VLOOKUP formula that generates the value.

I am looking for a formula that I can put in column F that will tell me if
the value in E is a VLOOKUP formula or not ...