Your box of games and flyers are very interesting. I'm also in contact with Paul Hilt the Sales Director and General Manager of PlayCable between 1981 and its closure in 1984. We have talked a bit about the final days of PlayCable, Paul had this to say...
"Toward the end of 1983, when it was clear the joint venture would be ending, GI approached me with an offer to basically stay 6 months to shut down PlayCable... Basically, I was tasked with negotiating out of the contracts I originally persuade them to sign.
Overall, the negotiations went well. Since Atari and Mattel Electronics business problems and losses were well known at that point, the cable operators were sympathetic to PlayCable's situation. I was authorized to keep the operators happy and, although I don't recall the details, the terms were pretty generous (e.g., Each subscriber would be sent 5 or so free cartridges; Corning test subscribers could keep the Intellivisions). I finally closed PlayCable's door in April 1984, however for all intents and purposes, PlayCable had been over in January 1984."
I think the 1983 closure date commonly quoted for PlayCable is just inaccurate. There is evidence out there for it limping through in at least some areas to 1984, and there is this article from CableVision sounding the closing bell.
The Corning test that Paul refers to was a trial that was run with one of the last cable companies to sign up to PlayCable in the summer of 1983, Corning NewChannels. Along with some other enhancements PlayCable loaned Intellivisions to Corning customers to see if removing this barrier to entry would raise uptake. The Intellivisions that were loaned out were defective ones returned to Mattel under warranty and which had been fixed and refurbished.
So it looks as though the box of games you have is one of the sets of five sent out to customers who were still subscribing to PlayCable in spring 1984. The 6 game outer packaging is standard Mattel retail packaging, so they were probably just saving money. The fact that the subscriber was in NJ and a customer of Suburban CableVision is interesting. They took PlayCable earlier, you can find their employees discussing PlayCable on p75 of the Feb 83 copy of Video Games Magazine, which has the only image of a real PlayCable menu screen - https://archive.org/details/Video_Games_Volume_1_Number_05_1983-02_Pumpkin_Press_US.
I wasn't aware of Suburban being part of the loaner Intellivision trial, but perhaps they were. I have seen suggestions that some cable companies sold the Intellivsion to their subscribers, but I've not found any hard evidence to back this up. I guess this might be an example of one of those. Certainly the brown box it is in suggests it has had a non-standard life.