Ribosomes are organelles that play a key role in the production and manufacture of proteins. Found throughout the cell, ribosomes are composed of ribosomal nucleic acid (rRNA) and protein. They are the sites of protein synthesis.
Although Robert Hooke first used a light microscope to look at cells in 1665, it was only during the last few decades that the cell's organelles were discovered. This is possibly because light microscopes do not have enough magnifying power required to see these tiniest of structures.
Ribosomes are found in two locations in the cell. Free ribosomes are dispersed throughout the cytoplasm. Bound ribosomes are attached to a membranous structure called the endoplasmic reticulum. Most cell proteins are produced by the free ribosomes. Bound riibosomes are instrumental in producing proteins that function within or across the cell membrane. Depending on the cell type, there can be as many as a few million ribosomes in a single cell. So no, different types of cells have differing numbers of ribosomes, depending on their need for protein manufacture.