accion publiciana or accion reinvidicatoria?

There is this parcel of lot(lot1) occupied by x, one of the successor of y for about 45 years. Y, in his lifetime, paid the real property taxes. Subject property was not yet covered by any title. Let say the land area is appoximately 250 sqm. upon Y's demise, X and the other co-heirs found out that said property was made subject to a catastral registration. (date is not certain). the property was reduced by few sqm. let say 5sqm. this 5sqm now forms part of the adjacent lot (lot2) which is now claimed and occupied by the adjacent owner. both the X and the adjacent owner knew that the cadastral survey was erroneous and in fact other owners within the area filed an application for correction of the cadastral survey because the lots they occupied prior to cadastral registration is different from the cadastral survey. x wanted to claim that 5 sqm... I hope someone could give me an advice about this.