I am assuming it is - though concerto grosso would normally refer to a small group of instruments set against the main orchestra, where as this is really a double violin concerto. There is probably not enough information to say this one is a totally positive identification, but this particular concerto is referred to as a concerto grosso in many sources - eg
http://www.dlib.indiana.edu/variatio...txt0001.html#2 gives a description of it. The Opus 3 concertos are for one, two, three and four violins, and are rightly admired as being among the best of Vivaldi.
The other ones I am pretty sure about. The sonata, as far as I know is a one off (there is a sinfonia as well with a similar name, but they are distinct works), and the Alla Rustica concerto RV151 is famous, so this will be the one. And no need to mention The Four Seasons!
I would go for the
Amazon compilation - I am betting its exactly the same recordings reassembled with a few others thrown in, and its only $4.98. What label is putting out recordings with EXL in their numberings I really don't know - I think it would be very hit or miss to find it. You could just buy separate disks containing the works - there are many more recommendable versions probably than this one.
If you click on credits for the album on the amg site it does actually list the performers:
Martin Sieghart Conductor, Harpsichord
Rainer Kussmaul Violin
Wolfgang Kussmaul Violin
Reinhard Werner Cello
Herwig Zack Violin
Stuttgart Chamber Orchestra Orchestra