Time to Change Spark Plugs?

So I was wondering if it was time to change the spark plugs.
Cause i bought the truck with 60,000 miles and I'm not sure exactly what was done to it, as far as maintenance.

Through researching I found that the factory used Denso on the left side and NGK on the right, although the plugs had 2 contacts on it. So I'm not sure if they were original or not.

I've attached a picture. Thanks

 

iirc, chris4x4 posted somewhere that tacos come from the factory w/diff brand plugs on each side .

i'd replace them.

[EDIT: I don't mean "i'd replace them" because they're diff brand plugs on each side...but, you've got them out, and it's time.]

 

i replaced my plugs at 102000 miles and yes they come factory with two different brands.