not sure offhand when they were first issued in full score. Schlesinger issued them posthumously in parts, and at least one of them (no.2) in a piano duet arrangement by his biographer Jahns, the latter in 1839: "Seconde Sinfonie, arr. p. Pfte à 4 Mains p. F.W. Jähns. Oe. posth. No. 1, in C . Berlin, Schlesinger 1 Thlr. 4 Gr. October, November 1839." -- HMB (see also
http://www.worldcat.org/title/seconde-s ... /919731121.)
(And from August 1839:
"Weber (C.M.de) Seconde Sinfonie p. grand Orchestre (in C.)" (Also Schlesinger. See
http://www.hofmeister.rhul.ac.uk/2008/c ... 39_08.html. Worldcat instances of this, e.g.
http://www.worldcat.org/title/sinfonie- ... /476658230, suggest that unsurprisingly this is parts- a practical matter!- not score.)
The first symphony was published by Schonenberger in Paris ca.1853 - also a piano reduction, though, again, sorry!... - though that'd be 1812 according to IMSLP (no further details given. How interesting. 1812? Hrm?) Though the first symphony _was_ published earlier than 1853, in a string quartet arrangement in (ca.?)1838 (by Jean André of Offenbach.)
Hrm. At the moment: don't know. Maybe Eulenburg's of the first symphony in 1948, and of the 2nd in 1970?...
One could compile one's own score from retypeset parts, of course, since the first published score doesn't seem to be -that- recent a thing either (
neatly, please - that is, a score is not just a bunched together collection of self-sufficient parts; when compiling the parts remove certain things)