Are they supposed to leak if you lay them on their side?

If not I have a bad one...

Any loss of fluid is a bad thing.

do you mean the struts or the inserts?

struts are usually filled with anti-freeze or something similar before the inserts are put in
so if your struts are leaking, it doesn't have to be all bad

if your inserts are leaking, you have a problem...

Really?

This isn't anti-freeze but oil. I'm going to pull it and have a better look.

I've heard of some guys using a light weight oil also. Mine had the original Boges in it and there was no fluid in the strut housings.

I've used oil many times.
its a good chance that your struts just have oil in them.

brant

The strut itself is filled with a coolant. Sometimes this is oil, like mineral oil or other lightweight oil. Sometimes it is filled with antifreeze. It is intended to assist with the transfer of heat.

So, as others have said, if it is the koni strut insert that is bad. If it is the loaded strut, not so bad.

All's good. Pulled the insert out and sure enough the strut was full of oil. It was leaking out from around the gland nut...

BTW, it's 112 here.