Good suggestion JE.
I've never owned or shot a MK 4, so had no experience with them. Just decided to research it before buying.
First thing was the price, $600 (later in the day was raised to $800). I thought the scope was a $1400 scope so was skeptical. It's actually a $1600 scope. A plain black box with no Leupold logo on it, and no Leupold owners manual. The seller said the scope was new, but he didn't have the box the scope came in, but he did have 41 pages of single side computer printed instructions stapled together.
The ocular bell fast focus wouldn't focus the reticle sharply, and the whole reticle light assembly looked identical to some I had seen on chinese scopes. The turret knobs had muddy feeling clicks. Finally, I thought all MK 4's were ffp's, so that was the convincer. I later found out that he LR/T's are 2nd plane reticles. The ER/T's are ffp's.
The exterior markings on the scope were well done....The scope itself looked real, but close examination and comparison against Leupold specs convinced me it was a fake.
I have owned and shot several VX-3 L/R's, and this scope couldn't match up with any of them.
On a weekend, you can't call the 800 # for serial number verification, so beware.
The old adage applies: if it seems too good to be true, it probably isn't.
Good hunting.
Tom