Yes bike pictured it is an Alan built frame. It is a Super Record frame as can be seen by the fancy lugs (cut-outs) and different set stays than the "regular" Alan frame...Alan built frames for a lot of high-end Italian builders.Guerciotti, Fabo and Colnago to name a few.
It is Italian built and uses a very different type of construction than other aluminum frames of the era....Alan's used the glue and screw method to build their frames. The Super Record also uses a thicker tubing to reduce frame flex a little.
There are many good articles on the net that have good information.
The price that you mention is a good number depending on the groupset....if it checks out I would buy it at that price, it is a great price if nicely equipped...I do not care for the crank in the pictures (too modern)....see what groupset is on the one you are considering as well as the lugs for cutouts to determine if SR.
There are a lot of naysayers out there regarding aluminum frames....Alans are a different breed...and most of the frame failures are based on anecdotal evidence. All materials wear out, but Alans have a good rep.realitive to other makes that have the tubes merely glued to the lugs.
As I said check it out..look at headset and bottom bracket for any cracks, that's where the most damage occurs.
I am prepping one for a build now and will start a thread soon.
Best, Ben