This is a pretty good episode, and I always enjoy watching it! I like the idea of suddenly Magnum is back in the 1930's, and trying to solve a 46 year old murder! The plot of this one was pretty cool, and tied in both the past and the present for an entertaining 1hr film-noir in color.
However, Magnum's car left little to be desired, in my opinion!

Tom Selleck looked so huge in this little..."scoot-about"!

But, I've always loved the past, and vintage/retro things...so I really get a kick out of "Flashback". Magnum's 1930's phone and the antique furniture were awesome!
However, at times things seem "choppy" in this episode, and don't quite flow as smoothly as they could have...I don't know, maybe it's just me? It just seemed like some of the performances/lines seemed "forced". But, maybe that was purposely done to make it seem like a 1930's murder-mystery movie? I will say, though, how Magnum supposedly just dreams all this and then when he wakes up all of it turns out to be exactly true, is a little silly and farfetched.
But, it was I guess supposed to be fantasy and reality mixing together...so overall this is one of season 3's best. I love T.C. in the past, and I also liked seeing Bogie-Rick returning.

"It was more ironic than a Robin Masters novel--she thought he was dead, he thought she was dead...and only the chauffeur knew the truth! He should have been the butler!" "Lest We Forget"