I've gotten some very convincing 80s key sounds out of Reason, but as others have said, NI FM8 is a good bet, as I'm sure Journey used the Yamaha DX7 on their stuff. There's a lot of other popular synths from that period they may have used too, such as Moog and Prophet 5. Overall though I've found that while Reason may not get you 100% accurate 80s synth sounds, it will get you so close it won't matter, and will even sound better in many ways.
A previous Backmask incarnation did metallized covers of Billy Idol's "Rebel Yell" and Berlin's "Metro" for an 80s theme show a few years back, I programmed all the synths with Reason, and it ended up sounding amazing, in many ways cooler than the original synth parts.