To judge the sizes the slide strips each measure 1-3/16'' x 5-1/2''. Aside from the two missing slides as stated above, the set appears to be in excellent condition as pictured.
Below here, for reference, is some additional information on the Historic Saugus Ironworks:
Saugus Iron Works National Historic Site
From Wikipedia, the free encyclopedia
Saugus Iron Works National Historic Site
U.S. National Register of Historic Places
U.S. National Historic Landmark District
U.S. National Historic Site
Location: 244 Central Street, Saugus, Massachusetts
Area: 9 acres (0.04 km)
Architect: Perry, Shaw & Hepburn, Kehoe & Dean
Visitation: 11,153 (2006)
NRHP Reference: #66000047
Significant dates
Added to NRHP: October 15, 1966
Designated NHLD: November 27, 1963
Designated NHS: April 5, 1968
Saugus Iron Works National Historic Site is a National Historic Site located about 10 miles (16 kilometers) northeast of Downtown Boston in Saugus, Massachusetts. It is the site of the first integrated ironworks in North America, founded by John Winthrop the Younger and in operation between 1646 and approximately 1670. It includes the reconstructed blast furnace, forge, rolling mill, shear, slitter and a quarter ton drop hammer. The facility is powered by seven large waterwheels, some of which are rigged to work in tandem with huge wooden gears connecting them. It has a wharf to load the iron onto ocean going vessels, as well as a large, restored 17th century house.