If the new CBA has the same rule regarding vets with 4 years' service, the tenders to Jones and Jackson won't mean anything - they will be unrestricted free agents. From what Jones has said - he wants to be a starter - I don't see him coming back. My guess is even if the Packers are willing to match another team's offer (Jones doesn't have to give them that chance if he's a UFA) he'll go to a team willing to start him. Another reason I think he's gone is how good Thompson and his staff are at finding WRs in the draft.
IMO Jackson has a much better chance of returning because I don't think any team will give him starter's money.
I believe the only way the tenders to these two matter is if the NFL and NFLPA agree to have another uncapped year and the chances of that are almost zero.