The shipping weights are certainly available in 2.0 (currently the bleeding edge), and I just confirmed that we had commented the UI out of 1.3 (for some reason... not sure why)
Anyway, you can add it back very easily by opening up the following file
/muraWRM/plugins/Slatwall/admin/product/producttabs/skus.cfm
and un-comment line 103, and then also the commented block from line 198-206.
That "should" work for now until 2.0 is a stable release.
-Greg