Got my last three carts from eBay vendors.  Robot Tank, Starmaster and Megamania.  Don't have natural light to take a picture of Megamania, so I'll provide it some other time.

Opening the Robot Tank cartridge, I found a surprise.  It uses a new blob-type ROM chip with all epoxy.  Of all the cartridges I opened in this project, this is the only one.  So most likely this was a latter run of Activision cartridges.  All the other ones had the larger chip. 

Here is the new one on the left, and my original cart on the right.  I ended up deciding that my original cart was going to be relabeled.  The folding looked worse and the end label was ripped.

Here is Starmaster and Robot Tank with the new labels.

Here is the comparison with the original labels.

Starmaster looks "off" with the new label.  The blue is a lot brighter and some of the stars in the screenshot are missing.  I noticed that there are a couple more cartridges were things were a tad off.  I will make a more detailed comparison in the near future.

Finally, here's a screenshot of the carts that I will most likely not relabel (except for Commando which I used my original cart to be relabeled, pictured here is the new one I got last week).  My Double Dragon cartridge is in really poor shape; I'll make it my next task to find a better cartridge considering it's one of my favourite games. I only wish I had my original collection from the early 90s!!!

A few more lessons learned:

- Some cartridges are absolutely filthy.  Over the 25 or so cartridges I opened to clean, I found dead bugs, substances I don't want to know about, rusty springs in the plastic prongs, and many times strong tobacco smell.

- If you place the new labels incorrectly, then there's not way to adjust it.  I put my Megamania one slightly off and tried to re-apply it.  It started to rip.  No do-overs with these labels

- Many of the cartridges on eBay claimed to be "tested" didn't work without a proper clean or scrub.  Megamania, River Raid, Kaboom, and Dolphin took ages to get working

- Surprisingly, my 7800 can play Robot Tank and Decathlon with no problems!