I'm certainly no authority on USATC motive power, but if French Wikipedia (!) is to be believed, the designation "Pershing" is properly applied only to engines delivered prior to the armistice of 11 November 1918 and so actually used by the US Army, whereas engines delivered after the armistice were "Feltons", and engines ordered in January 1919 or later specifically to supplement the rosters of major European railroads were called "Slades".
Since this engine in Romania is supposed to date from 1920, does that mean it's really a "Slade"?
fr.wikipedia.org
"Pour celles-ci il faut distinguer trois catégories, à savoir :
les machines effectivement utilisées par l'armée américaine qui porteront le surnom de Pershing
les machines en commande ou en construction après l'armistice qui porteront le surnom de Felton
et enfin les machines acquises directement par le Ministère, grâce à la loi du 10 janvier 1919 l'autorisant à acquérir du matériel pour compenser le manque de moyens des compagnies afin d'assurer le trafic, qui porteront le surnom de Slade."
(The source being Wikipedia, this may be just silly nitpicking by French foamers, so feel free to disregard.)
-Philip Marshall