No the 5 speed won't bolt up
I am doing this exact same swap only I want to do a D15Z1 for the gas mileage. I have 4 pics of trying to bolt up an 84 GW tranny to an 89 motor I had sitting in my shop. I have pics of why it won't work and where on the engine to the tranny mating it won't work. I would love to post the pics but for some reason I don't have the pictures and albums link like it says in the FAQ, maybe its cause I am new. I could try to email you pics though? Let me know if you are interested.
There are only 3 mounts on the 87 which may make it easier (in my book). You can either fab the mounts off of the 91 tranny to the existing positions of the motor mounts or you can cut off the brackets that the motor mounts hooked up to in the 91, they are probably spot welded to the firewall. If you pull the motor and tranny you could cut out these brackets and rehang them on the mounts that bolt to the motor. Then just hang the motor from above where you want it and weld the brackets in. I don't like permanently modifying anything like that because it means it will be in the way the next time I decide to swap to a different motor. I am thinking that I am going to make all my motor mounts out of heavy duty steel, like 1/2 inch thick, maybe less, I don't know yet. But that way if someone else wants to do the same I could send it off to get metal casted out of aluminum and they wouldn't have to fab anything.
I think I read somewhere that the 88-89 integra had a similar mount but it had an extra bracket bolted to it which is a great place to start for that mount. the 87 had a bracket that bolted to a spool mount, shouldn't be hard to coble up something off the side bracket and piece that sticks out of the timing cover for that one. Lastly, if I remember right the 4g civic, your 91, had the last mount bolted to the top of the tranny which allowed it to hang straight down. The 87 had something that looked L shaped. I would start at the top to make the pad and then do a wrap around C shape down around to the bottom of the tranny housing but extend the outer edge (inner edge is against the tranny) of the C from the bottom as an upward and out angle toward the front of the car and toward the rod piece that pokes through the tranny.
If I remember right I did one of those motors in my 89 lx and it came with a vacume advance distributor so hopefully you kept it.
Ahh now I can post pics!! as you can see the EW tranny won't bolt up to the D15B2 motor