Catalogued in RISM as “Concertos–C major; Manuscript copy; A-SEI V 1265” by Anonymus. RISM 600026060
Probable
The opening matches Koželuh's Symphony in C (PosK I:9), but only seven pitches are encoded and RISM catalogues the anonymous copy as a concerto.
Attributed copies compared (1 of 1 encoded incipit match):
1.1.1 Allegro di molto · i · 7 of 7 pitches agree
''4.C'8G''4.E'8B/{''CCCE}'4G8-''4.C'8G''4.E'8B/{''CCCE}'4G8-xG/4.A8E''4.C'8xG/{AAA''C}4E-/also RISM 450013478 1.1.1 Allegro molto
Catalogue data and incipits come from RISM (Répertoire International des Sources Musicales), CC BY 4.0. Incipits are rendered with Verovio. Source and data: https://github.com/aaymeloglu/rism-attributions.