Not as a complete absolute, IMHO. I think both George Kittle and Deebo have shown and possessed so much raw, explosive talent they probably wouldve been All-Pro weapons on other teams as well. Now, would they've been as successful from a purely stats and team-oriented standpoint where both men played in 4 NFCCGS and appeared and lost in two different SB's to same Chiefs team? Maybe not, but that again showcases Shanahan's genius in maximizing offensive players potential in his schemes. I mean, besides Kelce, Kittle has probably been the most dominant, potent pass-catching TE who can easily stretch secondaries and is also a damn good run-blocker, too in the NFL over the past 6-7 years along with Mark Andrews of Baltimore.
All-Pro playmakers like Kittle, Deebo, Fred Warner, Kinlaw and Nick Bosa aren't the easiest, "system guys" that are replaceable and lets keep in mind this core group of 49ers veterans had years to jell, work and develop into a potent, perennial playoff team. Chemistry and gradually fusing together all those different personalities where they precisely fit into Shanahan's unique offensive system can't be over-looked or dismissed. It also required a lot of time, fair amount of patience and diligent hard work.