The Guns of Gettysburg

I'm reading a book called "Summer Thunder" which is about the artillery used during the battle of Gettysburg.    It's also a tour guide of the various sites where artillery played a key role.  Yesterday I paid a visit down there and had a little time to kill so I decided to try to figure out how many canon are CURRENTLY on the battlefield.  I did not cover the entire battlefield so this will be a work in process:
6  In the Peach Orchard area enclosed by Birney Ave and the Wheatfield Road.
2  Along Sickles Road after turning from the Wheatfield Road
6  Along Wheatfield road, prior to reaching the Wheatfield
2  In the Wheatfield.
2  Near the intersection of Wheatfield Road and Crawford Ave.
2  Along Crawford Avenue prior to Devil's Den
4  Near Devil's Den
17  Along Sedgwick Rd, between Wheatfield Road and PA Monument
8  Near the PA monument
8 From PA monument to Copse of Trees
2  Near "book" monument
10 From the copse of trees to the Bairn farm, including 2 set back on walkway
6 after Bairn farm, including 2 set further back (may be same 2 as above)
24 on East Cemetery Hill
16 In Soldiers' cemetery
2  in Evergreen Cemetery
4  on Little Round top
64 on W. confederate avenue until Lee memorial (including 4 at end of walk)
13 From Lee memorial to Millerstown Road
15 From Millerstown Road to Emmitsburg Road
10 until far right of Confederate  line.
1 on the college campus.
4 on Jones Avenue
2 near Meade's HQ
8 along Emittsburg Road
1 Near the 3rd NY Monument
2 Near General Lee's HQ
4 Near the Reynolds/Buford monuments
4 Along Reynolds Avenue
7 on Oak Hill
2 along Seminary Ridge prior to W. Confederate avenue
12 on Benner Hill
10 along Howard avenue, including Barlow's knoll.
1 at George Spangler Farm
2 on Baltimore across from National Cemetery
1 on Middle Avenue

That's 284.