CIDIS Louviers lacquer cuts can be identified by "380" in the matrix. Being a full service provider, they would normally also press the records and print the covers there.
The printing can be verified if there is "Imp. C.I.D.S. Louviers" on the cover.
Vinyl pressings can be identified by 3 characters, identifying the ordering label, e.g.
ALA = Albatros, ATL = Atlantic, BAR = Barclay, CAR = Carrère, CHS = Chrysalis, COC = Cosmic Music, DEL = Delphine, ELE = Elektra, FON = Fontana, ISL = Island, MER = Mercury, PER = Pergola, PHI = Philips, POL = Polydor, RIE = Riviera, VER = Vertigo, VEV = Verve, VIR = Virgin, WAB = Warner Bros.
Format, channel and speed of a record can be identified by the following typical Philips matrix characters (e.g. 1F/2F) after the side identifier:
E stands for 7" 45 RPM EP Mono or Stereo.
F stands for 7" 45 RPM Mono.
L stands for 12" 33 1/3 RPM Mono.
M stands for 12" EP 45 RPM Stereo.
R stands for 10" 33 1/3 RPM Mono.
T stands for 7" 33 1/3 RPM Mono.
W stands for 7" 45 RPM Stereo.
Y stands for 12" Stereo (regardless the speed).
Other format identifiers are: PEP (7" EP), PPN (7" 45 RPM), LPR (10" LP Mono), LPL (LP Mono).
Renamed to PolyGram Record Service S.A. PRS, Louviers in 1979.