Let g be a simple finite dimensional Lie algebra. The category of graded finite dimensional modules over the current algebra g\otimes C[t] is not semi-simple and is known to admit several interesting infinite families of indecomposable objects, in particular the classical limits of the famous Kirillov-Reshetikhin modules. For g of classical types, the latter can be regarded as modules over the truncated current algebra g\tensor C[t]/(t ²). The category of graded representations of that algebra is "almost semi-simple". In particular, it turns out that endomorphism algebras of projective generators of suitable Serre subcategories are Koszul.